Heat exchanger



MarchlO, 1959 w, so v 2,877,000

HEAT EXCHANGER 6 Sheets-Sheet 1 i lllllllll Filed Sept. 16, 1955INVENTOR N v! fi m P ..4 0 K M mnr F. W. PERSON HEAT EXCHANGER March 10,1959 6 Sheets-Sheet 2 Filed Sept. 16, 1955 M/VE/VTUR FRANK W PERSONATTORNEY March 10, 1959 F. w. PERSON HEAT EXCHANGER 6 Sheets-Sheet 3Filed Sept. 16, 1955 //v VE/VTOR FRANK w. PERSON PM 03' ATTORNEY March10, 1959 F, w, PERSON 2,877,000

HEAT EXCHANGER Filed Sept. 16, 1955 6 Sheets-Sheet 4 g, FRANK w. pmsa/vATTORNEY March 10, 1959 F. w. PERSON 7,

I HEAT EXCHANGER Filed Sept. 16, v1955 6 Sheets-Sheet 5 m/ VEA/TOR J1!FRANK w. PERSON A r TQR/VEY March 10, 1959 F. w. PERSON 2,877,000

' HEAT EXCHANGER Filed Sept. 16, 1955 6 Sheets-Sheet 6 ""m. M Q F/G. Z

\JZQ T131 W J@ 1%: /J35 m #135 a 436 lA/VE/VTOR I I V A, W FRANK W.PERSON J ATTORNEY United States Patent IlEAT EXCHANGER Frank W. Person,Downers Grove,.-Ill., assignor to International Harvester Company, acorporationof New Jersey Application September 16, 1955, Serial No.534,791

7 Claims. (Cl. 257-245) This invention pertains to an improvement inheat exchangers.

Conventional heat exchangers usually comprise a pair of spaced headersor chambers suitably connected by a plurality of individual tubes. Thetubes in turn extend through a plurality of perforations or holesprovided in relatively thin laterally spaced fins. The manufacture ofthe individual fins, the tubes, and their subsequent assembly into asuitable heat exchanger core is a relatively costly operation and thoughnumerous machines and assembly techniques have been devised, heatexchanger cores are still relatively costly to manufacture. In thedevelopment of the welding art, a welding process has been devised whichpermits the relatively cheap manufacture of metal envelopes or membershaving as a necessarypart of their construction a plurality of tubularchannels. This process is performed under various trade names butgenerally it can be called a recrystallization process. In theperformance of the-process a fiat sheet, generally of aluminum orcopper, has applied thereto a parting agent or organic compound. Thisparting agent may be applied to the sheet in printed form, the patternof the said printing being the desired layout of the particular passageswhich are intended in the final product. A second sheet is then placedon top of the first-named sheet and both sheets are then subjected to acold welding process. Such a cold welding process involves the use ofpressure against the sheets and if necessary a low degree of heat may beemployed during the application of said pressure. As the pressure isapplied, a recrystallization of the contiguous sheets occurs therebywelding the said sheets together in all of the places except at thespots where'the parting agent has been applied to the original sheet.Thus a suitable envelope results, certain contiguous portions of theenvelope, however, not being welded together in view of the action ofthe parting agent or organic compound which has been used. The envelopeis then subjected to either hydraulic or pneumatic pressure. In otherwords, thespaces which are not welded together are connected to a sourceof hydraulic pressure and they are literally blown up causing theenvelopes to have a pluralitp of elongated bead-like projections whichform the passages desired'in the final product.

It has been found that this process is very inexpensive in manufacturingevaporator coils for refrigeration equipment. The so-called fins andtubular passages are thus integrally formed to provide an effectiveevaporator coil. It is a prime object of this invention, therefore,'toprovide an improved heat exchangerhaving a plurality of heat transfermembers with the passages and fins integrally formed and so disposed asto provide a more eificient construction which will also permit theapplication of the above mentioned process or similar processes in itsmanufacture.

A still further object is to provide an improved heat exchangerconsisting of a plurality of panels disposed in heat exchange relationto provide a circuitous passage for the flow of fluid therebet-ween.

A still further object is to provide an improvedheat exchanger whereinthe heat transfer members comprise a plurality of spaced envelopes whichcan'easily be assembled with the unit or disassembled for maintenancepurposes.

A still further object is to provide an improved heat exchanger for oilcoolers or radiators, the heat exchanger or transfer unit comprising aplurality of individual panelsadapted to be disposed in a position tosecure maximum heat transfer efficiency.

These and other objects will become more readily apparent from a readingof the specification when. examined in connection with the accompanyingsheets of drawings.

Figure 1 is a perspective'view, with a portion broken away, of a heatexchanger of a type generally utilized in connection with the cooling ofliquids such as. oil;

Figure 2 is a cross sectional view through the heat exchanger shown inFigure 1, the view being taken along the line 2-2;

Figure 3 is an enlarged cross sectional view taken substantially alongthe line 3-3 of Figure 2;

Figure 4 is a cross sectional view taken substantially along the line4-4 of Figure 2;

Figure 5 is a view similar to Figures 3 and 4 showing a modifieddisposal of certain heat exchange .members shown in Figures 1 through 4;

Figure 6 is a perspective view, with portions broken away to show theinterior of the unit, the said unit comprising a heat exchanger of atype generally utilized in connection with the cooling of liquids;

Figure 7 is an enlarged sectional view taken substantially along theline 7-7.0f Figure 6;

Figure 8 is a side elevational view ofa'heat transfer member or envelopeof a type usedin connection with the heat exchanger shown in Figure 6; 5

Figure 9 is a detailed view taken along the line 9- of Figure 8;

Figure 10 isa cross sectional view taken substantially along the line10-10 of Figure 8;

Figure 11 is a cross sectional view, in enlargedform, takensubstantially along the line 11-11- of Figure 8;

Figure 12 is an elevational view, similar to Figure 8, of another formof an envelope or heat exchangemember;

Figure 13 is a cross sectional View enlarged and taken substantiallyalong the line 13-13 of Figure 12;

Figure 14 is a perspective view of another modifiedtype of heatexchanger, the said view having portions broken away to show certaininterior portions of the unit;

Figure 15 is a cross sectional view taken along the line 15-15 of Figure14;

Figure 16 is a cross sectionalyiew, showing the disposition of aplurality of heat transfer members the said yiew being taken along theline -16-16 of Figure 15;

Figure 17 is a view similar to Figure 16, the said view bging takensubstantially along the line 17-17 ofFigure 1 Figure 18 is a perspectiveview of another modified type of heatexchange unit, the said view havingportions broken away to show an interiorportion of the invention;

Figure 19 'is a cross sectional view taken along the line 19-19 ofFigure 18;

Figure 20 is a cross sectional view, showing the-disposition of aplurality of heat transfer members, the said view being takensubstantially alongtheline 20-20 of Figure 19;

Figure 21 is a detailed view taken substantially'along the line 21-21 ofFigure 19;

Figure '22 is a perspective view of a heat exchanger of a radiator type;

Figure 23 is an enlarged plan view 'ofthe radiator 3 shown in Figure 22,the said view having certain portions broken away;

Figure 24 is a cross sectional view taken substantially along the line24-24 of Figure 23; and

Figure 25 is a sectional view, showing the disposition ofaplurality ofheat transfer members, the view being taken substantially along the line2525 of Figure 24. 1 Referring now particularly to Figures 1 through 4,a heat exchanger, suitable for the cooling of fluids, is generallydesignated by the reference character 10. The heat exchanger comprises ahousing or casing 11 having a front baffle or wall 12 and a rear bafileor wall 13 providing an inlet chamber 14 and an outlet chamber 15. Thechambers 14 and 15 also may be respectively considered as inlet headersand outlet headers. An inlet conduit or connection 16, provided on thecasing 11, is in communication with the inlet chamber 14. In similarfashion an outlet conduit or connection 17 is in communication with theoutlet chamber 15.

A plurality of heat transfer members or envelopes are designated at 18and 19. Each of the envelopes 18 and 19 is formed of a pair of sheetmetal members 20 which are positioned in contiguous relation. The sheetmetal members 20 may be of aluminum or copper, or similar non-corrosivematerial. Each of the sheet metal members 20 is provided with aplurality of horizontal arcuate projections 21, the said projectionsalso being described as of elongated bead-like construction. Each sheetmetal member further comprises a plurality of vertically disposedarcuate or bead-like projections 22 as best shown in Figure 2. Thebead-like projections 21 are disposed in relatively complementalrelation to provide a plurality of horizontally extending passages 23and the vertical bead-like projections 22 are also positioned incomplemental relation to provide a plurality of vertically extendingpassages 24. The arrangement of the passages 23 and 24 is different ineach of the members 18 and 19, this difference also being well shown inFigures 3 and 4. Each of the envelopes 18 and 19 is also provided withvertical end passages 25 communicating with the horizontal passages 23and vertical passages 24 and also providing for communication betweenthe chambers 14 and 15. t

The transfer members 18 and 19 may be easily and suitably made by theprocess described above. When manufactured by such a process the members18 and 19 are provided with a plurality of contiguous flat or bondedportions 26 which are disposed between the horizontal and verticalpassages 23 and 24, as indicated.

The heat transfer members 18 and 19 are positioned in vertical laterallyspaced relation as best shown in Figtires 2 and 3. Each vertical endpassage 25 communicates with either the chamber 14 or 15. The frontbaffies 12 and rear bafiies 13 are suitably slotted to accommodate themembers 18 and 19 and to retain the same in the said position. Aplurality of intermediate upper bafiles 27, as best shown in Figure 2,are provided within the casing 11. Each of the upper baffles is providedwith suitably slotted portions 28 to accommodate the transfer members 18and 19 and to suitably position the same within the casing. Likewise,the lower portion of the casing is provided with an intermediate lowerbaflle 29 also having suitably slotted portions 30 adapted to engage andmaintain the transfer members 18 and 19 in suitably positioned relation.Each of the transfer members 18 and 19 is provided withhorizontallyextending oppositely disposed marginal edge portions 31, these edgeportions being suitably in the slotted portions 28 and 30. The casing 11is also provided with an inlet connection 32 and an outlet connection33, as best shown inFigures l and 2. Fluid may be directed through theinlet connection 32, the same being-circulated in the manner disposedindicated by the arrows in a circuitous manner and 3' The referencecharacter 34, applied to the arrows, shows in efiect a circuitouspassage for the flow of the fluid which is directed to the inletconnection 32. As shown in Figure 4, this circuitous passage providedbetween the envelopes or transfer members permits the flow of fluid insuch a circuitous manner that it sweeps across the bead-like projectionsand causes a high maximum of heat transfer. For instance, the connection16 may be connected to the crank case of an engine so that hot oil flowsthrough the passages 23 and 24 and out through the outlet 17. As itflows through these passages, cooling fluid such as water, etc. may bedirected into the casing 11, the said fluid flowing in a circuitousandserpentine manner throughout the circuitous passages for eifectivelyand efliciently cooling the oil which is coursing through the passages23 and 24.

The contiguous fiat or bonded portions 26 also serve in the manner offins to permit heat transfer as the cooling liquid sweeps through thecircuitous arrangement of the bead-like projections. Thus a maximum heattransfer efliciency is effected. It can readily be seen that the lateralspacing of the transfer members 18 and 19 may be varied depending on theparticular construction desired. Similarly, the bead-like projectionscan be staggered in dilferent arrangements to secure maximum heattransfer efficiency. For instance, Figure 5 shows a variation in thedesign of the sheet metal members 20. Since the elements are essentiallythe same as in Figures 1 through 4, the same reference characters areapplied. In this particular case the vertical bead-like projections 22are of more shallow depth than these above described. It is apparent inthis modification that the outer surfaces of the vertical projections 22are disposed inwardly of the outer surfaces of the bead-like projections21. Thus by placing the transfer members 18 and 19 as shown in Figure 5,a nesting of the staggered horizontal bead-like projections is possibleto provide a greater number of the metal members in each heat exchangerand to decrease the size of the circuitous passages designated by thereference character 34 which is directed against the arrow showing thefluid flow. As indicated, the outer wall of the casing 11 may also beescalloped or formed to accommodate the change in shape of the sheetmetal members 20 and 21.

Referring now to Figures 6 through 13 a somewhat modified heatexchanger, designated by the reference character 40, is disclosed. Theheat exchanger 40 comprises a casing 41 having front baffles or walls 42and rear baflles or walls 43. The baffles 42 and 43 provide an inletchamber or header 44 and an outlet chamber or header 45. An inletconduit or connection 46 is in communication with the inlet chamber 44and an outlet connection 47 is in communication with the outlet chamber45.

As indicated in Figure 6, a plurality of envelopes or heat transfermembers 48 and 49 are positioned in upright laterally spaced relationwithin the casing 41. Each transfer member 48 and 49 comprises a pair ofsheet metal members 50, each of said members 50 being provided with aplurality of horizontal arcuate or bead-like projections 51 and aplurality of vertical arcuate or bead-like projections 52. The transfermembers 48 and 49 are similar to the ones above described and may bemade with the same process above disclosed. The bead-like projections 51of each member 50 are disposed in complemental relation to provide aplurality of horizontal passages 53. Similarly, the vertical projectionsare disposed in complemental relation to purovide a plurality ofvertical passages 54. Opposite ends of each transfer member 48 are alsoprovided with vertical end passages 55 in communication with thehorizontal and vertical passages 53 and 54, respectively. Only one ofthe vertical end passages 55 of each transfer member is shown in Figure6 though it is apparent that each transfer member has opposite,ver

tical end passages 55 in communication with either of the chambers 44and 45.

Each of the sheet metal members 50 is also provided with a plurality ofrelatively flat contiguous portions 56 disposed between the projections.As best shown in'Figure 6, the casing also includes a plurality ofintermediate upper baflles 57 of comb-shaped construction having fingersor teeth 58. Similarly, an intermediate lower baffle 59 is provided, thesame also having a plurality of spaced teeth 60. Each of the sheet metalmembershas the contiguous flat portions 56 suitably bonded by welding asindicated in the above mentioned process or'by other suitable bondingmeans. Furthermore, marginal edge portions 61 disposed on opposite sidesof the members 48 and 49 are also suitably bonded-together. By referringto Figure 6 it will be noted that the baflle 42 is slotted, as indicatedat 62, to accommodate the ends of the transfer members 48 and 49. Thewall or bafile 43 is similarly slotted.

As best shown in Figures 8 through 13, each of the transfer members 48and 49 is provided with a plurality of vertical grooves 63 which arerecessed in the surfaces of the vertical projections 52. When theenvelopes .48 and 49 are positioned in the casing, as shown in Figures 6and 7,'the teeth 58 and 60 respectively, of the members 57 and 59,engage the said grooves 63, thus suitably maintaining the members 48 and49 in suitable lateral spacing. Furthermore, the teeth serve to act asbafiies so as to direct the flow of liquid which courses into the casingin a circuitous manner between the projections and in a serpentinedirection as indicated by the arrows. As indicated by the arrows, thepassage thus provided by the baflles is relatively circuitous orserpentine as designated by the reference character 64 which is directedto the arrows showing the course of liquid.

Referring now to. Figures 14 through 17, another modified embodiment ofthe invention is disclosed. In these figures a heat exchanger 70comprises a casing 71 having an inlet header or chamber 72 and an outletheader or chamber 73. As best shown in Figure 15 a battle 74 and a Wall75 suitably separate said chambers. An inlet connection 76 is connectedto the casing for communication with the chamber 72 and an outletconnection 77 communicates with the chamber 73.

As best shown in Figures 16 and 17, a plurality of heat transfer membersor envelopes 78 are positioned within the casing 71. Each transfermember 78 consists of a pair of relatively thin sheet metal members 79,each of said members having a plurality of longitudinally extendingbead-like projections, the said projections being positioned incomplementary relation to provide a pair of generally U-shaped passages81. The members 78 also comprise a plurality of marginal connected edgeportions 82 and between the passages 81 a plurality of flat contiguousportions are provided on each of the members 78. As indicated by therecrystallization welding process above, the marginal contiguous edgeportions may be suitably welded together to provide a fairly rigidstructure with the passages provided therein. The heat trans fer members78 are positioned so that an opening 84, communicating with the passages81, is positioned within the chamber 72. Likewise, an opening 85 also incommunication with the passages 81 is positioned in the outlet chamber73.

Within the casing 71 there is provided also an inlet chamber 86 and anoutlet chamber 87 separated partially by means of a partition wall 88.As best shown in Figures 16 and 17, the bead-like projections of thetransfer members 78 are positioned in spaced relation to provide for thepassage of fluid or liquid therebetween. An inlet connection 89communicates with the chamber 86 and an outlet connection 90 providesfor the exhaust of liquid from the chamber 87. The circuitous passagesprovided by the adjacent transfer members are generally indicated by thereference character 91Which is directed towardthe arrows-showingtheparticular path of the liquid between'said transfer members. Thushere, like in the constructions above disclosed, the sheet metal memberswhich provide for the transfer of heat are. made simply in panel form bythe process described. Thus liquid flowing through the passages 81 canefiiciently be subjected to heat transfer by the flow of fluid throughthe various circuitous passages provided by the heat transfer members.Again it is, of course, obvious that variations .in the arrangement ofthe bead-likeprojections may be made so as in effect to staggerthem orto place them in cruciform relation as shown in the embodiments abovedisclosed.

Reference is now had to Figures 18 .through 21, wherein a heat exchangerincludes a casing 101 provided with laterally spaced headers or chambers102 and 103. Walls 104 separate the chambers 102 and 103, the .first ofwhich is an inlet chamber and the second being an outlet chamber. Aninlet connection 105 is in communication with the chamber 102 and anoutlet connection 106 is in communication with the chamber 103.

As best shown in Figure 20, a plurality of heat transfer members orenvelopes 107 are..positioned horizontally and in vertically spacedrelation. Each transfer member 107 is made of a relatively thin sheetmetal material having a plurality of bead-like projections 109positioned in serpentine relation to provide a passage 1-10. The 'sheetmetal transfer members 107 include oppositely disposed connectedmarginal edge portions 111 and relatively flat contiguous portions 112disposed between the passages 110. One end of the passage opens asindicated at 113 into the inlet chamber 102 and the other end of thepassage 110 opens as indicated at 114into the outlet chamber 103.

Within the casing 101an inlet chamber is designated at 115 and anoutletchamber at 116. The chambers 115 and 116 are separated by a partitionWall-117. The partition wall 117 is spaced from one wall of the casingto permit the flow of liquid from the inlet chamber 115 to the outletchamber 116. Thus it appears clear that fluid flowing into the chamber115 flows in a circuitous path, as indicated by the arrow, over theprojections and over the flat contiguous portions to effectively coolliquid flowing within the passages 110. The circuitous flow is,ofcourse, occasioned by the positioning of the'bead-like projections andthese, of course, can be positioned in a number of various arrangementsto provide different types of directed flow.

Figures 22 through 25 show a further modified embodiment of theinvention. Herein a heat exchanger is designated by the referencecharacter'120, the said exchanger being of the radiator type. Theexchanger 120 comprises a casing 121 having upper and lower headers orchambers 122 and 123. An inlet connection 124 directs liquid to theinlet header 122 and an outlet connection 125 discharges liquid from theheader 123. A radiator supply connection is indicated at 126.

The header 122 is provided with alower wall 127 and .the header 123 isprovided with an upper wall 128. A plurality of heat transfer members orenvelopesv 129 are positioned in upright relation and relativelylaterally spaced. The lower and upper walls 127 and 128 are suitablyslotted to permit the ends of the transfer members 129 to be disposed inthe headers 122 and 123. Each envelope or transfer member is comprisedof a pair of relatively thin metal sheets, each of said sheets havingbead-like projections which are disposed in complementary relation toprovide a plurality-of vertically extending passages 130 and 131. Hereagain the transfer members 129 may be made with a cold welding orrecrystallization process as above described. Each transfer membercomprises a plurality of flat contiguous portions 132 which are suitablybonded together. Likewise, opposite marginal edge portions 133 aresuitably bonded together so that each transfer member is relatively.rigid,

having the passages 130 and 131 disposed therein. As indicated in Figure24, each of the relatively thin members of the transfer members 129 isalso provided with a transversely extending bead 134, the said beadsbeing disposed in complemental relation to provide open end passages onopposite sides of the transfer members, the said passages 135 providingcommunication between the passages 130 and 131. An upper transferpassage of each transfer member is disposed within the header 122 andthe lower transfer passage 135 of each transfer member is disposed inthe lower header 123.

As indicated in Figure 25, the passages 130 and 131 are positioned inrelatively staggered relation so as to provide a plurality of circuitouspassages through which air may flow when the radiator is utilized as aheat exchanger. By staggering the bead-like projections in the mannerdisclosed, the passages 130 and 131 are staggered and air flow throughsaid passages is of circuitous direction to effectively create a maximumefliciency heat exchange efiect on the passages 130 and 131 and theliquid which is contained within the passages to be cooled. It is, ofcourse, obvious again that various different staggered arrangements canbe made, the most effective being, of course, the circuitous arrangementwhereby the air sweeps all surfaces of the heat transfer member toeffectively secure heat exchange eificiency.

Thus it is believed clear that various types of heat exchangers havebeen disclosed, each of said heat exchangers having novel type heattransfer members which may be manufactured by the simple processdescribed. Maintenance of a heat exchanger of this type is relativelysimple since all that need be done, if a transfer member is defective,is to remove the same and replace it with a new transfer member. Thetransfer members may thus be efiiciently and cheaply manufactured andvarious staggered patterns of the bead-like projections may be utilizedto secure the relatively circuitous passages which are disclosed. Inassembly the units, of course, are solder dipped in the conventionalmanner to secure sealing relation of the passages and the chambers asrequired.

Thus it is believed that the objects of the invention have been fullyachieved and that an improved heat exchanger and modifications thereofhave been fully disclosed. Further modifications may, of course, be madewhich do not depart from the spirit of the invention as disclosed northescope thereof as defined in the appended claims.

' What is claimed is:

1. A heat exchanger comprising a housing having spaced first chambersand a second chamber disposed adjacent said first chambers, a pluralityof transfer elements disposed in said second chamber, each elementcomprising a relatively thin member having contiguous flat portionsconnected together .and elongated raised portions positioned incomplementary relation to provide a plurality of passages extendinghorizontally and vertically in cruciform relation, said passagescommunicating with said first chambers, the horizontal passages of oneelement being positioned relative to the horizontal passages of anadjacent element in staggered relation with the raised portions of oneelement being disposed opposite to the flat portions of an adjacentelement to provide a plurality of circuitous passages within the secondchamber, a plurality of partitions within said second chamber, each ofsaid elements having a plurality of vertically extending slots disposedon opposite sides of said elements in alignment with the verticalpassages, each of said partitions being of comb-shape and having aplurality of teeth engaging said slots to divide said second chamberinto a plurality of sub-chambers whereby fluid flowing through saidcircuitous passages will move through said sub-chambers in meanderingfashion.

*2, A heat exchanger comprising a housing having spacedfirst chambersand a second chamber disposed adjacent said first chambers, a pluralityof transfer elements disposed in said second chamber, each elementcomprising a relatively thin metal sheet member having contiguous flatportions connected together and elongated raised portions positioned incomplementary relation to provide a plurality of passages extendinghorizontally and vertically in cruciform relation, said passagescommunicating with said first chambers, the horizontal passages of oneelement being positioned relative to the horizontal passages of anadjacent element in staggered relation with the raised portion of oneelement being disposed in opposite relation with respect to the flatportions of an adjacent element, to provide a plurality of secondcircuitous passages within said second chamber, a plurality ofpartitions within said second chamber, eachof said'elements having aplurality of vertically extending slots disposed on opposite sides ofsaid elements, each of said partitions being of comb-shape andhaving aplurality of teeth engaging said slots to divide said second chamberinto a plurality of subchambers whereby fluid flowing through saidcircuitous passages will move through said sub-chambers in meanderingfashion.

3. A heat exchanger comprising a housing having spaced first chambersand a second chamber disposed adjacent said first chambers, a pluralityof transfer elements disposed in said second chamber, each elementcomprising a relatively thin metal sheet member having contiguous flatportions connected together and elongated raised portions positioned incomplementary relation to provide a plurality of passages extendinghorizontally and vertically in cruciform relation, said passagescommunicating with said first chambers, certain passages of one elementbeing positioned relative to certain passages of an adjacent element instaggered relation, to provide a plurality of second circuitous passageswithin said second chamber, a plurality of partitions Within said secondchamber, each of said elements having a plurality of verticallyextending slots disposed on opposite sides of said elements, each ofsaid partitions being of comb-shape and having a plurality of teethengaging said slots to divide said second chamber into a plurality ofsub-chambers whereby fluid flowing through said circuitous passages willmove through said sub-chambers in meandering fashion.

4. A heat exchanger comprising a housing having spaced first chambersand a second chamber disposed adjacent said first chambers, a pluralityof transfer elements disposed in said second chamber, each elementcomprising a relatively thin member having contiguous flat portionsconnected together and elongated raised portions positioned incomplementary relation to provide a plurality of passages communicatingwith said first chambers, certain passages of one element beingpositioned relative to certain passages of an adjacent element instaggered relation with the raised portions of one element beingdisposed adjacent to and opposite the flat portions of an adjacentelement to provide a plurality of second circuitous passages within thechamber, a plurality of partitions within said second chamber, each ofsaid elements having a plurality of vertically extending slots disposedon opposite sides of said elements, each of said partitions being ofcomb-shape and having a plurality of teeth engaging said slots to dividesaid second chamber into a plurality of sub-chambers whereby fluidflowing through said circuitous passages will move through saidsub-chambers in meandering fashion.

5. A heat exchanger comprising a housing having spaced first chambersand a second chamber disposed adjacent said first chambers, a pluralityof transfer elements disposed in said second chamber, each elementcomprising a relatively thin metal sheet member having contiguous flatportions connected together and elongated raised portions positioned toprovide a plurality of passages communicating with said first chambers,the fiat and raised portions of one element being offset with respect'to the flat and raised portions of another element,

to provide a plurality of circuitous passages within said secondchamber, a plurality of partitions within said second chamber, each ofsaid elements having a plurality of vertically extending slots disposedon opposite sides of said elements, each of said partitions being ofcombshape and having a plurality of teeth engaging said slots to dividesaid second chamber into a plurality of subchambers whereby fluidflowing through said circuitous passages will move through saidsub-chambers in meandering fashion.

6. A heat exchanger comprising a housing having spaced first chambersand a second chamber disposed adjacent said first chambers, a pluralityof transfer elements disposed in said second chamber, each elementcomprising a relatively thin metal sheet member having contiguous flatportions connected together and elongated raised portions positioned toprovide a plurality of passages communicating with said first chambers,the flat and raised portions of one element being ofiset with respect tothe flat and raised portions of another element, to provide a pluralityof circuitous passages within said second chamher, a plurality ofpartitions within said second chamber, each of said partitions being ofcomb-shape and having a plurality of teeth disposed between saidelements to divide said second chamber into a plurality of sub-chamberswhereby fluid flowing through said circuitous passages will move throughsaid sub-chambers in meandering fashion.

7. A heat exchanger comprising a housing having spaced first chambersand a second chamber disposed adjacent said first chambers, a pluralityof transfer elements disposed in said second chamber, each elementcomprising a relatively thin member having contiguous flat portionsconnected together and elongated raised portions to provide a pluralityof passages communicating with said first chambers, the flat and raisedportions of one element being ofi'set with respect to the flat andraised portions of another element, to provide a plurality of circuitouspassages within said second chamber, a plurality of partitions withinsaid second chamber dividing said second chamber into a plurality ofsub-chambers whereby fluid flowing through said circuitous passages willmove through said sub-chambers in meandering fashion.

References Cited in the file of this patent UNITED STATES PATENTS

